i got some free solid pine doors that were stained dark and urethaned. I gave them a quick sand wiped down with mineral spirits and hit it with BIN primer(shellac based primer by Zinnser). I then spayed a coat of latex white paint. However, I am getting some areas that are a light brown in color as if it is bleeding through the paint. I let everything dry a few days and applied a 2nd coat. It is a little better but still seems to show. What might it be that caused this?I only notices it after i put the latex topcoat on, not after the primer.